Extraordinary cold episodes during the mid-Holocene in the Yangtze delta: Interruption of the earliest rice cultivating civilization

Abstract

In the estuary region of the Yangtze River (China), the oldest Neolithic civilization based on paddy rice cultivation flourished in the mid-Holocene (7.5–4.2 cal. kyr BP). However, although it is known that this Neolithic civilization collapsed at around 4.2 cal. kyr BP, the reason behind the collapse remains controversial. A sedimentary core (MD06-3040) collected from the inner shelf of the East China Sea, off the southeast coast of China, provides an excellent insight into estimate the Holocene regional paleoenvironment, including the alkenone based sea surface temperature (SST), atmospheric temperature (AT), and paleoproductivity. Extraordinarily severe abrupt cold episodes (i.e., 3–4 °C drop in SST) occurred frequently in the Yangtze delta region during 4.4–3.8 cal. kyr BP. These episodes could have been related to the global climatic transition called the “4.2 ka event”, when the East Asian monsoon hydrological regime might have been altered. The cold episodes could be sufficiently severe to damage rice cultivation and their occurrence constitutes a plausible explanation for the demise of the Yangtze Neolithic civilization.